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System Operations Challenges the work of CIGRE SC C2
Dr. Ir. Susana Almeida de Graaff
Delft, 3rd December 2020
EU context
Increasing shares of renewables
Development of European Internal Energy Market
Environmental drivers
Green Deal
Carbon neutrality by 2050
Affordable and cost efficient energy to end customer
by adequate market design, technological and operational innovations,
and sufficient grid capacity that play a role to balance cross-border supply and demand
World Context
Flexibility & Controllability
Observability & Integration
Sustainability & Energy
Efficiency
Usage of installed
technology capabilities
Cooperation Coordination
Regulation Harmonization
What are the system Needs?
How to achieve the targets?
Transition to RES Impact on System Operation
• Especially based on Wind and Solar Energy
• Increased volatility of renewables in the generation mix
• Increased operational uncertainty and risks
• Requires accurate forecast algorithms, predictability is important
• Often has priority and its curtailment is one of the last remedial actions
• Significant share embedded in the distribution network
• Long distance power transmission
• Security of supply under pressure: More volatile and increased power flows
• Volatile Markets and tending to become short-term oriented
• RES not yet structurally providing ancillary services
Decommissioning of Conventional PP Impact on System Operation
Decrease of system inertia
More frequent, faster and less damped dynamic phenomena are expected (e.g. larger fluctuations in frequency)
Reduction of short circuit power level:
Impact on fault current support
Larger voltage dips and larger propagation of low voltages during disturbances
Impacts the operation of protection relays
Impacts the active and reactive power reserves availability Decrease of redispatch possibilities, endangering network security Will conventional power plants keep on delivering system supporting services?
Prices expected to become more volatile: rise at times without wind or sun
Synchronous machines have been provided all flexibility needed to operate the power system … And now?
Operational Challenges
• Increased uncertainty due to RES volatility and more dynamic markets
• Volatile and increased power flows and long distance power transmission
• Operational complexity, which requires more decision support, integration and coordination
• More Observability and Controllability is necessary in the power system
• Optimal dispatch of flexibility options is needed to guarantee security of supply and affordability.
The grid is not a copper plate
Need for flexibility?
Strong need for flexibility
Flexible Power Reserves
Integration of new technology
Conventional Power Plants
Flexible Flow Control Classical Remedial Actions
DSR
Storage and EV
Flywheels
PEIG
FACTS
DC Links
Automatic Control SPS, WACS
Synchronous Condensers Cooperation and Coordination with DSOs
New requirements for PEID
• Inertia and Fast Frequency response
• Enhancement of disturbance ride through capabilities for voltage and frequency contingencies
• Ancillary Services provision from RES and ESS
• Active and Reactive power control using HVDC links or placing converters in end-to-end of corridors
• Power Oscillation Damping
• System restoration support
• New Grid forming control concepts - PE needs to behave as a voltage source, synchronize with others, behave properly in islanded mode, take care of overcurrent limitation, be compatible with conventional machines and other grid following PE.
• Develop adaptive protection system - capable of correctly operating in different operating conditions (e.g. with high PE penetration and low short circuit power levels)
• Adequate network models
Need for Observability/Controllability?
Access to “lots” of DATA
Data exchange Platforms
EMERGING TOOLS
Big Data Analytics, Artificial Intelligence, Machine Learning for AWARENESS and DECISION SUPPORT
(e.g. Hybrid SE, DSA, WAMS, Optimisation)
New Generation of SCADA EMS systems
Accurate data FORECAST to reduce the operational uncertainty
Automatic Power Flow Control, SIPS and WACS (PMUs) using fast available flexibility
to keep system Stability
Preparing for a cyber-physical system
More Extreme weather events already today!
An adequacy situation, e.g. as this month in California, is different from a tornado or an
earthquake that will cause permanent damage to the infrastructure.
The consequences of a blackout are also strictly connected to correct operation protection and
control systems. E.g. during emergency situations that cause UFLS is crucial to keep critical
loads in service.
Critical situations e.g. caused by severe weather conditions, that turned into success stories,
and the lights stayed on:
• Cold weather operation at MISO in January 2019 (MISO operated with extreme cold, with
unplanned generation outages. The emergency operational procedures were activated and
MISO reliably met all obligations)
• Separation of SA January-February 2020, the islanding event lasted for 17 days (crucial
support also from available flexibility which includes BESS installed and VPP in SA). This
occurred during an extremely hot summer in Australia full of many other operational challenges.
More Extreme weather events already today!
15/08/2020: California USA (source: Preliminary Root Cause Analysis Rotating Outages August 2020)
• Rolling blackouts in CAISO (Flex Alert)
Extreme heat in across Western US , expected cloud cover
that will reduce PV output, and wildfires threatening power lines
Electricity demand exceeding the existing electricity resource planning
targets, amplified by the extreme heat.
Need for flexibility
• Lessons learned
Update the resource and reliability planning targets
Ensure that the generation and storage projects are completed by their targeted dates
Increase flexibility: Expedite the regulatory and procurement processes to develop additional
resources that can be online by 2021
Enhance market practices to ensure they accurately reflect the actual balance of supply and demand
during stressed operating conditions
130 - 150 mph winds and 12.5 foot storm surge
51.88 inches of rainfall causing flooding in 50 counties
Spawned tornadoes in Texas, Louisiana, Alabama, Mississippi, Tennessee and North Carolina
42,000 lightning strikes
$125 billion in damages
More Extreme weather events already today!
Welcome to the world of CIGRE
• A global community for the collaborative development and sharing of power system expertise
• Not for profit, established in Paris, France 1921
• A long history as a key player in the development of the power system
• Produces reference publications based on practical experience and analysed data
• An open, engaging, fact-based culture
• Connecting power systems professionals from all over the globe
(https://www.youtube.com/watch?v=HgZE2V-I1NE)
CIGRE’s Strategic Directions
1. Future Power System
2. Environment and Sustainability
3. Best use of Existing Systems
4. Unbiased Information for all Stakeholders
CIGRE’s Domain of Work
Group A – Equipment: A1 Rotating electrical machines
A2 Power transformers and reactors
A3 Transmission and distribution
equipment
Group B – Technologies: B1 Insulated cables
B2 Overhead lines
B3 Substations and electrical
installations
B4 DC systems and power
electronics
B5 Protection and automation
Group C – Systems: C1 Power system development and
economics
C2 Power system operation and
control
C3 Power system environmental
performance
C4 Power system technical
performance
C5 Electricity markets and
regulation
C6 Active distribution systems and
distributed energy resources
Group D – New materials & IT: D1 Materials and emerging test
techniques
D2 Information systems and
telecommunication
Strategic Directions of SC C2
Overview of WG led by SC C2
WG C2.26
Power system restoration accounting for
a rapidly changing power system and
generation mix
Babak Badrzadeh (AU)
WG C2.17
Wide area monitoring systems – Support
for control room application
Walter Sattinger (CH)
WG C2.24
Mitigating the risk of fire starts and the
consequences of fires near overhead
lines for System Operations
Frank Crisci (AU)
SC Secretary
Vinay Sewdien (NL)
WG C2.39
Operator Training in Electricity Grids at
Different Control Levels and for Different
Participants/Actors in the New
Environment
Jayme Darriba Macedo (BR)
Publication Advisor
Anjan Bose (US)
SC C2 Chair
Susana de Graaff (NL)
Strategic Advisory Group
Susana de Graaff (NL)
JWG C2/C4.41
Impact of high penetration of inverter-
based generation on system inertia of
networks
Mpeli Rampokanyo (SA)
Real time System Operation and Control
System Operational Planning and
Performance Analysis
Control Centre Infrastructure and
Human Resources for System Operation
Joint Working Groups
Tutorial Advisory Group
Jens Jacobs (DE)
WG C2.40
TSO-DSO Cooperation – Control Centre
Tools Requirements
Michael Power (IE)
WG C2.25
Operating Strategies and Preparedness
for System Operational Resilience
Jens Jacobs (DE)
JWG C2/B4.38
Capabilities and requirements definition
for Power Electronics based technology
for secure and efficient system operation
and control
Jan van Putten (NL)
More information on SC C2 activities: www.c2.cigre.org
C2.17 – Wide Area Monitoring Systems – Support for Control Room Applications
WAMS systems = knowledge of system dynamic performance which is currently not available in the SCADA/EMS
Control room operators need simple and intuitive system dynamic awareness
C2.17
C2.17
C2.17
Benefits in real-time: alarm on occurrence of large/poorly damped oscillations
Participating regions
Regions contributing to problems where measures help
Monitoring inertia (frequency stability)
Wide area control for fast frequency response
Monitoring of phase angle (transient/voltage stability)
Support for black start and power system restoration
Conclusions
https://e-cigre.org/publication/750-
wide-area-monitoring-systems--
support-for-control-room-applications
C2.24 - Mitigating the risk of fire starts and the consequences of fires near overhead lines for System Operations
C2.24
Challenges tackled:
Risk of powerlines starting fires increases significantly on extreme fire danger days
Powerline-caused fire meaning extreme fire danger
Risk of powerline equipment damage increases when wildfires burn out of control
Climate change means:
• More heatwaves
• More days of extreme fire danger
• More days when powerlines could start a fire
• More days when wildfires may occur and damage powerlines
Challenges:
• What can utilities do to stop fires
• What can utilities do to mitigate the consequences of wildfires
Expected outcome: survey on fire start and strategies to avoid the risk of fire and its consequences
C2.25 - Operating Strategies and Preparedness for System Operational Resilience
In power system operations, resilience generally means the ability to respond quickly to and recover from a disruption. To enhance system resilience, various strategies from the provision of sophisticated operation and control capabilities to preparing for the effective and prudent operations can be considered.
The increased awareness of the potential adverse impact on power system operations from physical and cyber invasions, high impact low frequency (HILF) events and increased frequency of system disturbances caused by natural phenomena (hurricanes, earthquakes, etc.), results in a shift in the focus of the energy industry from purely developing preventive measures towards providing and enhancing resilience following these major disturbances (interruptions).
WG C2.25 focuses on operational resilience, i.e. the operating and control strategies and risk mitigation preparedness that can support system operators to more effectively manage system disturbances, restore the disrupted power grid to a secure state and eventually to its pre-disturbance state.
C2.25 - Lessons Learned USA
Identify areas of enhancement or improvement to strengthen operational resilience
Vegetation
Management
Drones Distribution Automation Devices
Staging Sites
Mobile Substations
Pole Hardening and
Inspections
C2.26 - Power system restoration accounting for a rapidly changing power system and generation mix
Source: AEMO
C2.26 Value proposition
Challenges posed due to increased uptake of inverter connected generation, both large-scale and distributed energy resources
The use of inverter connected generation for black starting/system restart support
The use of distribution network for black starting/system restart support
The use of HVDC links for “black” starting/system restart support
System restart testing involving wider transmission and distribution networks
Interactions with cybersecurity
Applications and types of offline power system modelling and simulation tools
Tools and techniques for control rooms
C2.39 - Operator training in electricity grids at different control levels and for different participants/actors in the new environment
• Understanding of a more complex environment
• Knowledge regarding dynamic phenomena
• Need for more analysis closer to real-time
• New technologies
Operators Training &
Knowledge Management
Source: CIGRE TB 524
C2.40 - TSO-DSO Co-operation – Control centre tools requirements
Vertical Coordination
Coordination TSO-DSO
Access to flexibility (frequency reserves),
voltage control and congestion
management with DSO-TSO interaction
Fuel
Cell
The role of this CIGRE WG is to specify a set of control centre tools for both the TSO and DSO to manage and operate this newly evolved power system. The critical aspect that is addressed is that the tools must enable a very high level of co-operation between the TSO and DSO so that they can efficiently address system issues at the different levels.
With increasing power electronics
interfaced devices, the system
behaviour and response are bound to
change. It identifies issues on new
power system behaviour (e.g. lower
resonance frequencies due to
increasing HVAC underground cables).
Identifies areas where how we operate the power
system needs to change. It includes the people,
processes and tools in system operation that
observe the bulk electric system and take necessary
actions to maintain operational reliability. The new
operation of the power system will require to
increase the level of automatic control actions to
cope with the expected faster and more frequent
dynamic power system behavior. Some phenomena
are expected to be too fast for a manual
operational response.
System stability will remain crucial. This
category deals with issues that result from
lack of support for a stable voltage and
frequency (e.g. increasing RoCoF resulting
from decreasing synchronous generation).
C2/B4.38 - Capabilities and requirements definition for Power Electronics based technology for secure and efficient system operation and control
C2/B4.38 - Capabilities and requirements definition for Power Electronics based technology for secure and efficient system operation and control
https://e-cigre.org/publication/821-capabilities-and-requirements-
definition-for-power-electronics-based-technology-for-secure-and-
efficient-system-operation-and-control
C2/B4.38 Mapping Table Power Electronics Interfaced Devices
HVDC PE based FACTS PE based generation
Operational Challenges VSC
HVDC LCC HVDC STATCOM SVC TCSC SSSC UPFC IPFC PV
WTG
Type III
WTG
Type IV BESS
Lack
of
volt
age
&
fre
qu
en
cy s
up
po
rt Increasing RoCoF ✓ ✓ ✓ ✓ ✓
Decreasing frequency nadir ✓ ✓ ✓ ✓ ✓
Excessive frequency deviations ✓ ✓ ✓
Static reactive power balance ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Dynamic reactive power balance ✓ ✓ ✓ ✓ ✓ ✓
Ramps management ✓ ✓
Estimation of operating reserves
Ne
w o
pe
rati
on
of
the
po
we
r sy
ste
m
Increased congestion
Observability of RES
Controllability of RES
Vertical coordination
Horizontal coordination
Operation of hybrid systems
Control of bi-directional flows ✓ ✓
New operator skills
Power system restoration ✓ ✓ ✓ ✓
New
beh
avio
ur
of
the
po
wer
sys
tem
Resonances due to cables and PE ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Reduction of transient stability
Resonance instability ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Sub-synchronous controller interaction ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
New low frequency oscillations ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Decreased damping ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Voltage dip induced frequency dip ✓ ✓
Larger voltage dips ✓ ✓
PLL instability ✓
LCC commutation failure
Asymmetry withstand capability of PE ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Supply of single-phase traction load
C2/C4.41 - Impact of high penetration of inverter-based generation on system inertia of networks
In this JWG primary frequency response studies will be carried out in order to analyse and mitigate against the impact of the reduction of synchronous inertial energy on the power system as a result of integration of non-synchronous renewable generation using various networks around the globe as case studies.
The JWG addresses amongst others the following issues:
Define operational measures to manage the dispatch of inertia and reduce the risk when operating with low inertia on the system.
Quantify Primary Frequency Requirements with increasing RES penetration
Demand Response requirements
Primary Reserves requirements
Fast Frequency Response techniques and requirements
Methodology to establish rate of change of frequency limits with increasing non-synchronous RES penetration levels, and the integration of the methodology into the operational environment.
Investigate possible control strategies for inverter-based generation in order to provide wider future designs possibilities of inverters/converters and to achieve the most efficient way to use the technology.
C2/C4.41
Impact of increasing RE generation on system inertia
C2/C4.41: Example Frequency Support – Australia
Battery Energy Storage System
In South Australia, there is a 100 MW (129 MWh) BESS installation at Hornsdale, and a 30 MW (8 MWh) BESS installation at Dalrymple.
One of the aims of these batteries is to provide frequency control ancillary services.
On 14 December 2017 successful operation was demonstrated. The battery in Hornsdale discharged with millisecond response to immediately arrest the frequency excursion following a trip of a 560 MW coal fired power plant.
Reference:
F. Crisci et al., “Power System Restoration – World Practices &
Future Trends,” CIGRE Sci. Eng. J., vol. 14, pp. 6–22, 2019.
Hornsdale power reserve response to disturbance of 14 December 2017
C2/C4.41: Example Frequency Support - Netherlands
Pool of assets
In 2016, a pilot project was initiated in the Netherlands with the aim to provide frequency containment reserves by aggregating responses from a pool of assets: electrical vehicles, heat-pumps, Bio-CHPs, battery installations, residential energy storage and wind turbines
Reference:
D. Klaar, “Pilot projects for ancillary services,” in Proceedings of the 2018
CIGRE Session, 2018
Response of FCR pilot assets to frequency deviation
Geographical distribution of SC C2 members
CIGRE Science and Engineering Journal
CSE Journal is a full open access journal referenced by Scopus
The Journal accepts submission from industry as well academia
The peer review is done by some of the wold’s top experts
More information: https://www.cigre.org/GB/publications/cigre-cse
Looking into the future …
How much more complex will the future power system be in comparison to
today? One thing is certain…
We need innovation and R&D in the electrical energy business!
